1. Field
Example embodiments relate to an apparatus and method of obtaining a depth image, and more particularly, to an apparatus and method of obtaining a depth image which may accurately measure a long maximum measurement distance.
2. Description of the Related Art
Currently, information about a three-dimensional (3D) image is widely used in a variety of applications. In general, 3D information includes geometry information and color information.
Geometry information may be obtained using a depth image. A depth image may be indirectly obtained using software called computer vision technology, or directly obtained using a hardware device such as a depth camera.
A method of measuring a Time of Flight (TOF), which is the time taken for an emitted ray to be reflected back from an object, is widely used as a method of obtaining a depth image of a depth camera.
The method of obtaining a depth image may include direct and indirect methods. In the direct method, a time when a reflection ray reaches a receiving unit is sensed using an element sensitive to light, such as a Single Photon Avalanche Photodiode (SPAD), which is used to measure a TOF. In the indirect method, a phase difference of when pulse light modulated using a photodiode is reflected back is detected as a charge.
In the indirect method, when a pulse width uses a great amount of light, a maximum measurement distance increases and a precision of a depth image decreases. When a pulse width uses a small amount of light, a precision of a depth image increases and a maximum measurement distance decreases.